Broiler Vaccination

What is vaccination

Vaccination is the process of introducing a vaccine containing weakened, inactivated, or partial components of a pathogen into the body to stimulate immunity against a specific disease. When the immune system encounters the vaccine, it responds by producing antibodies and activating immune cells. This leads to the formation of immune memory cells, which allow the body to recognize and respond more quickly and effectively if exposed to the actual disease in the future. In many cases, a properly vaccinated individual may never develop the disease, and even if infection occurs, the illness is often milder because the immune system can respond quickly. As a result, vaccination helps protect individuals from infection or reduces the severity of the disease.

Vaccination is only one part of flock health, not a substitute for it. Good biosecurity, clean water, adequate ventilation, correct stocking density, clean litter, and pest control all matter just as much. A vaccine will not cure birds that are already sick.

Common vaccines given to broilers

• Marek's vaccine: This vaccine protects against Marek's disease (a viral disease) and is administered to day-old chicks at the hatchery. Farmers do not need to repeat this vaccination, as it is presumed to have already been given at the hatchery. Additionally, since broilers are usually slaughtered before the disease has time to manifest, the risk is generally minimal for a typical grow-out period.
• Gumboro vaccine: This vaccine protects against a viral disease by name Gumboro (Infectious Bursal Disease), which attacks the bursa of Fabricius and can weaken a young bird's overall immune response.
• Lasota vaccine: This vaccine protects against Newcastle disease (a viral disease).

Vaccination schedule at a glance

Dose count is based on flock size. Choose enough vaccine doses to cover the entire flock, using the available vial sizes. For example, if a 50-dose vial is available, 50 birds require 50 doses. If a 50-dose vial is not available, a 100-dose vial can be used for 50 birds.

The same principle applies as the flock size increases:

• 51–100 birds: 100 doses
• 101–150 birds: 150 doses (100 + 50) or 200 doses
• 151–200 birds: 200 doses
• 201–250 birds: 250 doses (200 + 50) or 300 doses
• 251–300 birds: 300 doses
• Larger flocks: continue the same approach.

The required dose quantity does not have to come from a single vial. Available vial sizes can be combined to provide the required number of doses. For example, 300 doses can be supplied as one 200-dose vial plus one 100-dose vial.

Before vaccination

1. Avoid giving any drugs the day before vaccination (some drugs can interfere with the vaccine). If you must give something, stick to a multivitamin.
2. Check the vaccine name, expiry date, and dose count on the label before you buy or use it.
3. Keep the vaccine cold from the point of purchase through to use — don't let it sit in a warm vehicle or under sun on the way home.
4. Vaccinate only healthy birds. If the flock is already sick, hold off and seek advice first.
5. Use clean drinkers and equipment, and make sure any disinfectant residue has been rinsed off before preparing vaccine water — residual disinfectant can kill a live vaccine.
6. Plan the timing so the prepared vaccine mixture is used immediately rather than left standing.

How to administer a water-based vaccine

Gumboro and Lasota are both typically given through drinking water, and the general procedure is similar for both — only the day of administration differs. The volume of water may also differ. Follow these steps for either vaccine:

1. Withhold water first. Withhold water from the birds for 2–3 hours before vaccination so they will be thirsty enough to finish the vaccine water quickly. Vaccination is usually carried out in the morning, for example, around 9:00AM.
2. Prepare the water. Use clean, non-chlorinated water where possible. The amount of water required depends on the vaccine, the age of the birds, and the number of doses being administered. Check the table under the relevant vaccine below for the recommended water volume. If chlorinated water is the only option available, use milk, preferably skimmed milk, to help neutralize the effect of the chlorine. Mix the milk into the water before adding the vaccine. Some farmers also add milk as a precaution even when the water isn't chlorinated.
3. Mix in the vaccine. Keep the vaccine in cold storage until the moment of use. Once removed, immediately submerge the vial, open it underwater, and empty its contents into the prepared water. A reconstituted live vaccine loses potency quickly, so use the mixture within 1–2 hours and keep it out of direct sunlight — don't prepare it in advance.
4. Distribute to the birds. Stir the mixture, pour it into the drinkers, and serve it to the flock. Use a foot dip when entering or leaving the pen while giving the vaccine, to avoid contaminating your farm.
5. Disinfect afterward. Place the empty vaccine container and anything used to stir the mixture into a separate container of water with a disinfectant such as Hypo, then rinse thoroughly. Also pour some disinfectant on the spot where you mixed the vaccine. Dispose of the empty container and used water far away from the farm — this step is very important for biosecurity.
6. Support recovery. Give the birds a multivitamin immediately after vaccination — for example, one teaspoon of Vitalax per 4 litres of water — to help them recover from the stress of vaccination.

A second dose is given later in the schedule because maternal antibodies passed from the hen can block the first dose in some chicks, and uneven water intake means not every bird gets a full dose the first time. The second round catches those birds and boosts immunity in the rest.

Gumboro Vaccine

The first dose is given on day 7, followed by a second dose on day 21, using the water administration procedure described above. Because Gumboro attacks the bursa of Fabricius — central to a young bird's developing immune system — getting both doses on schedule matters more here than for most other broiler vaccines: a bird whose bursa is already damaged responds poorly to any vaccine given afterward. If your area has high Gumboro pressure or your chicks have low maternal antibodies, a vet may recommend adjusting this timing.

Quantity of water needed to administer the vaccine

The quantity of water needed depends on the age of the birds and the dosage required. The table below shows the recommended amounts:

Lasota Vaccine

The first dose is given on day 14, followed by a second dose on day 28, using the same water administration procedure described earlier. Lasota is a live vaccine used to help protect chickens against Newcastle disease, a highly contagious viral disease that can spread rapidly through a flock and cause serious illness and death. Because Newcastle disease can spread quickly, ensuring that birds receive the vaccine properly is important for effective flock protection.

Quantity of water needed to administer the vaccine

The table below shows the quantity of water needed for the first dose and second dose for the various dosages of Lasota vaccine:

After vaccination

• Watch the flock over the following days for unusual reactions, weakness, breathing difficulty, or a rise in mortality.
• Keep temperature, ventilation, litter condition, and water access at their normal good standard — vaccination stress is easier to shake off in a comfortable environment.
• Keep a simple record of the date, vaccine name, batch number, dose, and route for each vaccination round — this makes it much easier to troubleshoot if something goes wrong later.

If birds become severely ill or deaths increase noticeably after vaccination, contact a poultry veterinarian promptly.